The problem of control of the emission of noxious or deleterious fumes, vapors or the like from automobile engines has received considerable attention, resulting in numerous proposals. One proposal essentially universally adopted is the PCV which leads oil fumes from the crankcase to the engine intake. Other proposals have included the recycling of a portion of the exhaust gas, as in U.S. Pat. No. 3,237,615, by introducing somewhat cooled exhaust gas to the intake system below the carburetor by induction manifold vacuum. However, this and similar proposals have not resulted in the emission control desired, because the effective mixing of fuel with the intake air by the carburetor has been vitiated by a concentration of exhaust gases in various portions of the mixture, or concentrations in various cylinders. Although additional air has been added to the carburetor for assisting combustion during idling, as in U.S. Pat. No. 3,768,789, or supplemental air has been introduced to the intake manifold of an engine fitted with a PCV valve, as in U.S. Pat. No. 3,946,710, or between the carburetor and the intake manifold in larger quantity during engine deceleration, as in U.S. Pat. No. 3,564,580, this additional air has not been introduced in a manner corresponding to that of the present invention.